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Why doesn't anyone talk about the supply side bonding jumper in the atx power supply when discussing ground loops?

The bonding jumper that is the easiest place to break the ground loop in the system? I’ve opened up an NZXT 750W, a corsair 850W and Dell oem 685w. They all have it, the Dell had two- 2 corners of the pcb of the power supply. Slip two fibre washers and replace with same screws. After doing this I can run a 3.5mm out to any av reciever(mains powered) without a ground loop isolater inline and no noise.

The problem with removing the DC side earth ground is that now the entire DC side of the switcher is floating above ground. That potential can become dangerous. If you have a voltmeter, check the minus side of DC versus ground and see just how far above earth ground your supply is running…

To give you an example, at work we use some DIN rail mounted Phoenix AC to DC switching power supplies. When we remove the grounding strap between the DC side and the earth ground, the DC side of the supply floats to ~60V above ground. This can be unsafe.

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  1. I suppose the answer is now?
  2. So it floats- its contained in a metal housing bonded to earth. What is going to get energized that can come in contact with a user?

By isolating the supply, anything attached to that supply can now float above the ground plane. That means all the things being powered by the supply are also floating with that same potential above the earth ground. I’m not saying I know for certain all that can happen, I just know the potential is there and the supply was designed with an earth ground for a reason.

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If I had to guess its there to get listed by Underwirters Laboratories and be rated “intrinsically safe.”
For example with the jumper in place say whatever inside is energized in the p.s. on the secondary side gets loose and contacts the interior surface- it has the equipment ground( earth) for secondary ocp to act against. Remove the jumper and the same fault condition will result in the supply burning up most likely.
It’s just that 2 decades time I’ve seen soldered wires break loose but never in atx supply.
Also I’ve come home to a quiet and stinky( burnt p.s.) more times than I’ve had failed spinning rust.
I guess I’m now comfortable with them failing catastrophically.

With regard to everything else floating- no. The motherboard is still seeing the fifth wire through the mounting screws. The same as the shell of the power supply case which is still bonded.

It seems what your doing is more risky, it’s just that you’re willing to accept that risk to get clean audio. A ground loop noise isolator isn’t an expensive piece of equipment, but if you’re comfortable with the risk that comes from removing the safety grounds in your PSU, I get it.

I have a similar “Don’t tell me the odds” mindset with some things I do as well.